League of Legends is a video game inspired by the Defense of the Ancients (DotA) map for Warcraft III: The Frozen Throne developed and published by Riot Games for Microsoft Windows. It was first announced on October 7, 2008, and released on October 27, 2009. The game was in a closed beta from April 10, 2009, to October 22, 2009. It then transitioned to open beta until release.

General

Players are formed into 2 even teams with 1–5 champions on each team. Each team starts at opposing sides of a map, near what is called a "Nexus". A match is won when either the opposing team's Nexus is destroyed or the other team surrenders. To destroy a Nexus, each team must work through a series of towers called "Turrets". Turrets are often placed along a path to each base referred to as a "Lane". Along the way, each player must gain levels from killing the opposing team's "Champions" and "Minions" (small NPCs that constantly spawn and attack the other team) and defeating neutral monsters (some of which grant buffs known as Crests upon death). Also, champions purchase "Items" with in-match gold to improve their champion. In League of Legends, each player starts at level 1 at the beginning of the match and can obtain the maximum of level 18 with their champion, leveling 4 different champion-specific abilities.

Game modes and matchmaking

League of Legends is a session-based game. Matchmaking occurs based on the average Elo ratings of each individual players, with slight proprietary adjustments.

The game can currently be played in four different modes: tutorial, practice, normal and ranked.

Tutorial is the game mode where new player are directed to when they first start the game. It is a private offline game session where the players are taught the basic controls and goals of the game.

Custom mode allows players to manually create custom game sessions that other players can find on a game list and join. Players can add computer controlled champions (bots), set password, and set the maximum number of players in Custom games.

Co-op vs. AI is a mode where players are matched either alone or as part of a group against a team of bots. Currently, this mode is only available on the 5v5 map, Summoner's Rift. Players can choose either beginner or intermediate difficulty.

In a Normal game, players queue themselves to the automatic match-making service either alone (Solo) or as part of a group. The server then automatically creates a game and attempts to populate it with players in a way that both sides have a 50% chance to win.The players are rated in a hidden Elo rating based on the outcome of normal mode matches they participate in, and the server uses that rating for future match-making.Only the win count of the player in normal mode is displayed publicly, losses and Elo are not displayed.

The Ranked mode became available to players of level 20 and higher when Season One officially commenced on July 13, 2010, but was later changed to only be available to players of level 30 (players can still queue for Ranked games if they're over level 20, but only if they are in an arranged team).While this mode plays much like Normal mode, two main differences exist. First, the game uses Draft Mode where each team can ban 2 champions from the game (so no players may play them) and the two teams cannot play the same champion (so if team A takes Ezreal, team B cannot take Ezreal). Second, an exclusive, visible rating is calculated based on the player's performance in Ranked games. The player is placed on the ladder according to their rating, and top teams on the ladder have a chance to compete in the "$100,000 Global Finals" at the end of the season.

Fields of Justice

Maps in League of Legends are called Fields of Justice.There are currently two Fields of Justice that the players can choose from:

Summoner's Rift resembles the DotA map. It has 3 lanes and supports 5 players per side.

Twisted Treeline is a smaller map with only 2 lanes. It supports 3 players per side. Because of the shorter average lifespans of games in this map, you receive 22% reduced XP and IP when you finish the game.

There are two other maps, the tutorial map called Proving Grounds and the new map that is in development with the name of Magma Chamber.

A match puts two teams with a fixed number of players against each other. Each team has its base, which contains the re-spawn point, item shop and nexus. The two bases are connected by lanes. Periodically, waves of minions spawn from the nexus. Minions are AI-controlled troops that walk down the lanes, engaging any enemies they encounter. The lanes are lined with turrets that engage enemies within range. Once a turret is destroyed, it cannot be rebuilt. A new element in League of Legends is the inhibitors. Each lane has an inhibitor on both ends. If a team destroys the enemy inhibitor, more powerful "super minions" will spawn for that side. Unlike turrets, inhibitors respawn after a fixed amount of time.

Besides the lanes, the maps also contain "jungle" areas. Neutral monsters inhabit the jungle. These monsters can be killed by a champion for bonus gold and experience. Some powerful neutral monsters grant the killer a temporary buff that will help them in battle (such as slowing the enemy and gaining more attack damage, increased damage and increased health regeneration, or an increased mana regeneration and spell cooldown reduction). Another special terrain feature is the brush. Brush blocks the line of sight of units, allowing champions to hide and set up an ambush.

The goal of each team is to destroy the enemy Nexus. The first team to achieve this is the victor. Victory is also attained if your opponent surrenders, using a voting system, but only 17 minutes (Twisted Treeline) or 20 minutes (Summoner's Rift) or more into the game.

Champions

A Champion is a hero unit that levels up over the course of the match. Each Champion has unique abilities and is tagged with properties such as 'tank' and 'silence' to describe their play style and notable ability traits. The game was released with 40 Champions, but Riot continued to create new champions post-release using a development pipeline. The pipeline allowed Riot to release a new champion every few weeks even though it now takes much longer to develop one. There are 72 Champions as of March 22, 2011.

At the start of each match, every player chooses a champion to fight for him in battle. The choice of champions is limited by what the player has unlocked. Each week, certain champions are made temporarily free so that players can try them out without unlocking them.

Champions gain experience by killing enemy minions, champions or buildings. After reaching a certain amount of experience, the champion levels up. Each level increases the champion's stats and adds an ability point that can be spent to improve one of the Champion's unique abilities. The maximum level for a champion is 18.

Players are given base gold at a slow rate throughout the game, and they must acquire more gold either by landing the killing blow on an enemy minion (also known as "Last-Hitting"), killing a champion, killing neutral monsters, or destroying enemy Turrets. Some abilities and items also generate extra gold. The acquired gold can be spent at the item shop for various items. Some items can be combined into more powerful ones by following predefined recipes These items empower the champions and buying the right items for a champion is a main part of the game's strategy. Numerous large websites are made by fans to share and discuss item/champion combinations and guides.

Persistence and meta-game

Summoner

The Summoner acts as the persistent element in the game, to be used to track statistics and scores for each player.

Summoners gain experience points and Influence Points for each battle they participate in. They level up by getting enough experience, unlocking new ways to influence battles.

The Summoner can also choose two summoner spells to bring with it into an in-game session on the Fields of Justice. These spells significantly impact gameplay, and have a high cooldown while costing no mana. All spells can be improved by masteries.

Masteries

Masteries are perks that affect gameplay, they are commonly referred to in other games as "skill-trees". All of the masteries are passive effects although some augment summoner spells, which can be activated. They are grouped into Offensive, Defensive, and Utility categories. Each group has 6 tiers, within a group all but the first tier are locked when you first start, with a successive tier opening with each 4 points spent in the same group. Lines in the mastery tree imply additional unlocking criteria. The summoner can put one point per level (up to level 30) into masteries. Masteries can be re-distributed at will between battles.

Runes

Similar to masteries, runes affect gameplay in minor ways. Runes are categorized into Marks (offensive), Seals (defensive), Glyphs (magic) and Quintessence (all-purpose). They are also grouped into 3 tiers, higher tiers requiring a higher Summoner level. Runes must be unlocked in the Store and it is possible to have more than one copy of a rune. Summoners must arrange their runes in the Runebook to benefit from them. The Runebook has limited number of slots for each rune type. The book has two pages, allowing two different rune builds to be saved and the appropriate one chosen before a battle. More rune pages can be purchased from either Influence Points or Riot Points, however the 7 rune page combo can only be purchased with Riot Points. A combining system exists for runes: combining two equal-tier runes produces a random rune of the same tier, while combining 5 equal-tier runes produces a higher-tier rune.

Store

The League of Legends Store allows Summoners to purchase additional options through Riot Points (RP) and Influence Points (IP). Riot Points must be bought using real money, while Influence Points are earned by playing the game.

Champions can be unlocked for either RP or IP.

Skins are alternate looks for champions that can be unlocked for RP only.

Boosts that can increase the amount of IP or XP gained per game over a period can be purchased for RP only.

Runes can be purchased for IP only so as to not directly "sell power".

Others, which are only rune pages at the moment, purchased with IP or RP.

Bundles that unlock a large selection of champions can be purchased for RP only.

Competitive play

League of Legends has experienced some moderate success in the competitive video game field. The 2010 WCG Grand Finals at Los Angeles hosted a competitive tournament for League of Legends. The competitors came from around the world to compete, coming from China, Europe and the Americas. The victors were the Counter Logic Gaming team from North America and won a seven-thousand dollar prize